Individuals With SARS-CoV-2 Infection During the First and Second Waves in Catalonia, Spain: Retrospective...

Area of Science:

• Epidemiology
• Infectious Diseases
• Public Health

Background:

• Understanding the evolution of SARS-CoV-2 (the virus causing COVID-19) is crucial for public health.
• Comparing different waves of infection helps identify changes in disease epidemiology and patient profiles.
• Adapting health services requires knowledge of how patient characteristics and outcomes vary across infection waves.

Purpose of the Study:

• To describe the epidemiology of suspected SARS-CoV-2 infection.
• To characterize patients with positive SARS-CoV-2 tests during the first and second waves in Catalonia, Spain.
• To compare the severity and outcomes of COVID-19 patients between the two waves.

Main Methods:

• Retrospective cohort study comparing two distinct periods of the COVID-19 pandemic in Catalonia.
• Analysis of SARS-CoV-2 infection data, including testing numbers, positive results, and hospitalizations.
• Definition of patient severity based on hospital admission, intensive care unit (ICU) stay, or death.

Main Results:

• The second wave had significantly more tests (140,332 vs. 26,096) and cases (11,800 vs. 3,140) than the first.
• The first wave had a higher percentage of positive tests (12.0% vs. 8.4%) and hospitalizations (26.1% vs. 5.8%).
• Individuals in the first wave were older, had more comorbidities, and presented with worse health conditions compared to the second wave.

Conclusions:

• SARS-CoV-2 infection characteristics differed significantly between the first and second waves.
• The first wave disproportionately affected older individuals with poorer health outcomes.
• Improved surveillance systems in the second wave aided in detecting more asymptomatic cases and contacts, contributing to pandemic control.